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Inline(3) |
User Contributed Perl Documentation |
Inline(3) |
Inline - Write Perl Subroutines in Other Programming Languages
This document describes Inline version 0.86.
use Inline C;
print "9 + 16 = ", add(9, 16), "\n";
print "9 - 16 = ", subtract(9, 16), "\n";
__END__
__C__
int add(int x, int y) {
return x + y;
}
int subtract(int x, int y) {
return x - y;
}
The Inline module allows you to put source code from other programming languages
directly "inline" in a Perl script or module. The code is
automatically compiled as needed, and then loaded for immediate access from
Perl.
Inline saves you from the hassle of having to write and compile
your own glue code using facilities like XS or SWIG. Simply type the code
where you want it and run your Perl as normal. All the hairy details are
handled for you. The compilation and installation of your code chunks all
happen transparently; all you will notice is the delay of compilation on the
first run.
The Inline code only gets compiled the first time you run it (or
whenever it is modified) so you only take the performance hit once. Code
that is Inlined into distributed modules (like on the CPAN) will get
compiled when the module is installed, so the end user will never notice the
compilation time.
Best of all, it works the same on both Unix and Microsoft Windows.
See Inline- Support for support information.
Do you want to know "Why would I use other languages in Perl?" or
"Why should I use Inline to do it?"? I'll try to answer both.
- Why would I use other languages in Perl?
- The most obvious reason is performance. For an interpreted language, Perl
is very fast. Many people will say "Anything Perl can do, C can do
faster". (They never mention the development time :-) Anyway, you may
be able to remove a bottleneck in your Perl code by using another
language, without having to write the entire program in that language.
This keeps your overall development time down, because you're using Perl
for all of the non-critical code.
Another reason is to access functionality from existing API-s
that use the language. Some of this code may only be available in binary
form. But by creating small subroutines in the native language, you can
"glue" existing libraries to your Perl. As a user of the CPAN,
you know that code reuse is a good thing. So why throw away those
Fortran libraries just yet?
If you are using Inline with the C language, then you can
access the full internals of Perl itself. This opens up the floodgates
to both extreme power and peril.
Maybe the best reason is "Because you want to!".
Diversity keeps the world interesting. TMTOWTDI!
- Why should I use Inline to do it?
- There are already two major facilities for extending Perl with C. They are
XS and SWIG. Both are similar in their capabilities, at least as far as
Perl is concerned. And both of them are quite difficult to learn compared
to Inline.
There is a big fat learning curve involved with setting up and
using the XS environment. You need to get quite intimate with the
following docs:
- perlxs
- perlxstut
- perlapi
- perlguts
- perlmod
- h2xs
- xsubpp
- ExtUtils::MakeMaker
With Inline you can be up and running in minutes. There is a C
Cookbook with lots of short but complete programs that you can extend to
your real-life problems. No need to learn about the complicated build
process going on in the background. You don't even need to compile the code
yourself. Inline takes care of every last detail except writing the C
code.
Perl programmers cannot be bothered with silly things like
compiling. "Tweak, Run, Tweak, Run" is our way of life. Inline
does all the dirty work for you.
Another advantage of Inline is that you can use it directly in a
script. You can even use it in a Perl one-liner. With XS and SWIG, you
always set up an entirely separate module. Even if you only have one or two
functions. Inline makes easy things easy, and hard things possible. Just
like Perl.
Finally, Inline supports several programming languages (not just C
and C++). As of this writing, Inline has support for C, C++, Java, Python,
Ruby, Tcl, Assembler, Basic, Guile, Befunge, Octave, Awk, BC, TT (Template
Toolkit), WebChat and even PERL. New Inline Language Support Modules (ILSMs)
are regularly being added. See Inline-API for details on how to create your
own ILSM.
Inline is a little bit different than most of the Perl modules that you are used
to. It doesn't import any functions into your namespace and it doesn't have
any object oriented methods. Its entire interface (with two minor exceptions)
is specified through the 'use Inline ...' command.
This section will explain all of the different ways to
"use Inline". If you want to begin using C
with Inline immediately, see Inline::C-Cookbook.
The most basic form for using Inline is:
use Inline X => "X source code";
where 'X' is one of the supported Inline programming languages.
The second parameter identifies the source code that you want to bind to
Perl. The source code can be specified using any of the following
syntaxes:
- The DATA Keyword.
-
use Inline Java => 'DATA';
# Perl code goes here ...
__DATA__
__Java__
/* Java code goes here ... */
The easiest and most visually clean way to specify your source
code in an Inline Perl program is to use the special
"DATA" keyword. This tells Inline to
look for a special marker in your
"DATA" filehandle's input stream. In
this example the special marker is
"__Java__", which is the programming
language surrounded by double underscores.
In case you've forgotten, the
"DATA" pseudo file is comprised of all
the text after the "__END__" or
"__DATA__" section of your program. If
you're working outside the "main"
package, you'd best use the "__DATA__"
marker or else Inline will not find your code.
Using this scheme keeps your Perl code at the top, and all the
ugly Java stuff down below where it belongs. This is visually clean and
makes for more maintainable code. An excellent side benefit is that you
don't have to escape any characters like you might in a Perl string. The
source code is verbatim. For these reasons, I prefer this method the
most.
The only problem with this style is that since Perl can't read
the "DATA" filehandle until runtime,
it obviously can't bind your functions until runtime. The net effect of
this is that you can't use your Inline functions as barewords (without
predeclaring them) because Perl has no idea they exist during compile
time.
- The FILE and BELOW keywords.
-
use Inline::Files;
use Inline Java => 'file';
# Perl code goes here ...
__JAVA__
/* Java code goes here ... */
This is the newest method of specifying your source code. It
makes use of the Perl module
"Inline::Files" written by Damian
Conway. The basic style and meaning are the same as for the
"DATA" keyword, but there are a few
syntactic and semantic twists.
First, you must say 'use Inline::Files' before you 'use
Inline' code that needs those files. The special
'"DATA"' keyword is replaced by either
'"file"' or
'"below"'. This allows for the bad pun
idiom of:
use Inline C => 'below';
You can omit the "__DATA__"
tag now. Inline::Files is a source filter that will remove these
sections from your program before Perl compiles it. They are then
available for Inline to make use of. And since this can all be done at
compile time, you don't have to worry about the caveats of the 'DATA'
keyword.
This module has a couple small gotchas. Since Inline::Files
only recognizes file markers with capital letters, you must specify the
capital form of your language name. Also, there is a startup time
penalty for using a source code filter.
At this point Inline::Files is alpha software and use of it is
experimental. Inline's integration of this module is also fledgling at
the time being. One of things I plan to do with Inline::Files is to get
line number info so when an extension doesn't compile, the error
messages will point to the correct source file and line number.
My best advice is to use Inline::Files for testing (especially
as support for it improves), but use DATA for production and
distributed/CPAN code.
- Strings
-
use Inline Java => <<'END';
/* Java code goes here ... */
END
# Perl code goes here ...
You also just specify the source code as a single string. A
handy way to write the string is to use Perl's "here document"
style of quoting. This is ok for small functions but can get unwieldy in
the large. On the other hand, the string variant probably has the least
startup penalty and all functions are bound at compile time.
If you wish to put the string into a scalar variable, please
be aware that the "use" statement is a
compile time directive. As such, all the variables it uses must also be
set at compile time, "before" the 'use
Inline' statement. Here is one way to do it:
my $code;
BEGIN {
$code = <<END;
/* Java code goes here ... */
END
}
use Inline Java => $code;
# Perl code goes here ...
- The bind() Function
- An alternative to using the BEGIN block method is to specify the source
code at run time using the 'Inline->bind()' method. (This is one
of the interface exceptions mentioned above) The
"bind()" method takes the same arguments
as 'use Inline ...'.
my $code = <<END;
/* Java code goes here ... */
END
Inline->bind(Java => $code);
You can think of "bind()" as
a way to "eval()" code in other
programming languages.
Although bind() is a powerful feature, it is not
recommended for use in Inline based modules. In fact, it won't work at
all for installable modules. See instructions below for creating modules
with Inline.
- Other Methods
- The source code for Inline can also be specified as an external filename,
a reference to a subroutine that returns source code, or a reference to an
array that contains lines of source code. (Note that if the external
source file is in the current directory it must be specified with a
leading '.' - ie '.file.ext' instead of simply 'file.ext'.)
These methods are less frequently used but may be useful in some
situations.
For instance, to load your C++ code from a file named the same
as your perl module with a swapped file extension, you can use:
use Inline CPP => (__FILE__ =~ s/\.pm$/.cpp/r);
- Shorthand
- If you are using the 'DATA' or 'file' methods described above and
there are no extra parameters, you can omit the keyword altogether. For
example:
use Inline 'Java';
# Perl code goes here ...
__DATA__
__Java__
/* Java code goes here ... */
or
use Inline::Files;
use Inline 'Java';
# Perl code goes here ...
__JAVA__
/* Java code goes here ... */
If you are writing a module, you can also use the DATA section for POD and
AutoLoader subroutines. Just be sure to put them before the first Inline
marker. If you install the helper module
"Inline::Filters", you can even use POD
inside your Inline code. You just have to specify a filter to strip it out.
You can also specify multiple Inline sections, possibly in
different programming languages. Here is another example:
# The module Foo.pm
package Foo;
use AutoLoader;
use Inline C;
use Inline C => DATA => filters => 'Strip_POD';
use Inline Python;
1;
__DATA__
sub marine {
# This is an autoloaded subroutine
}
=head1 External subroutines
=cut
__C__
/* First C section */
__C__
/* Second C section */
=head1 My C Function
Some POD doc.
=cut
__Python__
"""A Python Section"""
An important thing to remember is that you need to have one
"use Inline Foo =>
'DATA'" for each "__Foo__"
marker, and they must be in the same order. This allows you to apply
different configuration options to each section.
Inline tries to do the right thing as often as possible. But sometimes you may
need to override the default actions. This is easy to do. Simply list the
Inline configuration options after the regular Inline parameters. All
configuration options are specified as (key, value) pairs.
use Inline (C => 'DATA',
directory => './inline_dir',
libs => '-lfoo',
inc => '-I/foo/include',
prefix => 'XXX_',
warnings => 0,
);
You can also specify the configuration options on a separate
Inline call like this:
use Inline (C => Config =>
directory => './inline_dir',
libs => '-lfoo',
inc => '-I/foo/include',
prefix => 'XXX_',
warnings => 0,
);
use Inline C => <<'END_OF_C_CODE';
The special keyword 'Config' tells Inline
that this is a configuration-only call. No source code will be compiled or
bound to Perl.
If you want to specify global configuration options that don't
apply to a particular language, just leave the language out of the call.
Like this:
use Inline Config => warnings => 0;
The Config options are inherited and additive. You can use as many
Config calls as you want. And you can apply different options to different
code sections. When a source code section is passed in, Inline will apply
whichever options have been specified up to that point. Here is a complex
configuration example:
use Inline (Config =>
directory => './inline_dir',
);
use Inline (C => Config =>
libs => '-lglobal',
);
use Inline (C => 'DATA', # First C Section
libs => ['-llocal1', '-llocal2'],
);
use Inline (Config =>
warnings => 0,
);
use Inline (Python => 'DATA', # First Python Section
libs => '-lmypython1',
);
use Inline (C => 'DATA', # Second C Section
libs => [undef, '-llocal3'],
);
The first "Config" applies to
all subsequent calls. The second "Config"
applies to all subsequent "C" sections
(but not "Python" sections). In the first
"C" section, the external libraries
"global",
"local1" and
"local2" are used. (Most options allow
either string or array ref forms, and do the right thing.) The
"Python" section does not use the
"global" library, but does use the same
"DIRECTORY", and has warnings turned off.
The second "C" section only uses the
"local3" library. That's because a value
of "undef" resets the additive
behavior.
The "directory" and
"warnings" options are generic Inline
options. All other options are language specific. To find out what the
"C" options do, see
"Inline::C".
If a particular config option has value options of 1 and 0, you can use the
'enable' and 'disable' modifiers. In other words, this:
use Inline Config =>
force_build => 1,
clean_after_build => 0;
could be reworded as:
use Inline Config =>
enable => force_build =>
disable => clean_after_build;
Inline has a special configuration syntax that tells it to get more
configuration options from other Perl modules. Here is an example:
use Inline with => 'Event';
This tells Inline to load the module
"Event.pm" and ask it for configuration
information. Since "Event" has a C API of
its own, it can pass Inline all of the information it needs to be able to
use "Event" C callbacks seamlessly.
That means that you don't need to specify the typemaps, shared
libraries, include files and other information required to get this to
work.
You can specify a single module or a list of them. Like:
use Inline with => qw(Event Foo Bar);
Currently, modules that works with Inline include
"Event",
"PDL", and those that use
"Alien::Build".
In order to make your module work with Inline in
this way, your module needs to provide a class method called
"Inline" that takes an Inline language as
a parameter (e.g. "C"), and returns a reference to a hash with
configuration information that is acceptable to the relevant ILSM. For C,
see C Configuration Options. E.g.:
my $confighashref = Event->Inline('C'); # only supports C in 1.21
# hashref contains keys INC, TYPEMAPS, MYEXTLIB, AUTO_INCLUDE, BOOT
If your module uses ExtUtils::Depends version 0.400 or higher,
your module only needs this:
package Module;
use autouse Module::Install::Files => qw(Inline);
Inline lets you set many configuration options from the command line. These
options are called 'shortcuts'. They can be very handy, especially when you
only want to set the options temporarily, for say, debugging.
For instance, to get some general information about your Inline
code in the script "Foo.pl", use the
command:
perl -MInline=info Foo.pl
If you want to force your code to compile, even if its already
done, use:
perl -MInline=force Foo.pl
If you want to do both, use:
perl -MInline=info -MInline=force Foo.pl
or better yet:
perl -MInline=info,force Foo.pl
Inline needs a place to build your code and to install the results of the build.
It uses a single directory named '.Inline/' under
normal circumstances. If you create this directory in your home directory, the
current directory or in the directory where your program resides, Inline will
find and use it. You can also specify it in the environment variable
"PERL_INLINE_DIRECTORY" or directly in your
program, by using the "directory" keyword
option. If Inline cannot find the directory in any of these places it will
create a '_Inline/' directory in either your current
directory or the directory where your script resides.
One of the key factors to using Inline successfully, is
understanding this directory. When developing code it is usually best to
create this directory (or let Inline do it) in your current directory.
Remember that there is nothing sacred about this directory except that it
holds your compiled code. Feel free to delete it at any time. Inline will
simply start from scratch and recompile your code on the next run. If you
have several programs that you want to force to recompile, just delete your
'.Inline/' directory.
It is probably best to have a separate
'.Inline/' directory for each project that you are
working on. You may want to keep stable code in the <.Inline/> in your
home directory. On multi-user systems, each user should have their own
'.Inline/' directories. It could be a security risk
to put the directory in a shared place like
"/tmp/".
All programmers make mistakes. When you make a mistake with Inline, like writing
bad C code, you'll get a big error report on your screen. This report tells
you where to look to do the debugging. Some languages may also dump out the
error messages generated from the build.
When Inline needs to build something it creates a subdirectory
under your "DIRECTORY/build/" directory.
This is where it writes all the components it needs to build your extension.
Things like XS files, Makefiles and output log files.
If everything goes OK, Inline will delete this subdirectory. If
there is an error, Inline will leave the directory intact and print its
location. The idea is that you are supposed to go into that directory and
figure out what happened.
Read the doc for your particular Inline Language Support Module
for more information.
Inline keeps a cached file of all of the Inline Language Support Module's meta
data in a file called "config". This file
can be found in your "directory" directory.
If the file does not exist, Inline creates a new one. It will search your
system for any module beginning with
"Inline::". It will then call that module's
"register()" method to get useful
information for future invocations.
Whenever you add a new ILSM, you should delete this file so that
Inline will auto-discover your newly installed language module. (This should
no longer be necessary as of Inline-0.49.)
This section lists all of the generic Inline configuration options. For language
specific configuration, see the doc for that language.
- "directory"
- The "directory" config option is the
directory that Inline uses to both build and install an extension.
Normally Inline will search in a bunch of known places for a
directory called '.Inline/'. Failing that, it
will create a directory called '_Inline/'
If you want to specify your own directory, use this
configuration option.
Note that you must create the
"directory" directory yourself. Inline
will not do it for you.
- "name"
- You can use this option to set the name of your Inline extension object
module. For example:
use Inline C => 'DATA',
name => 'Foo::Bar';
would cause your C code to be compiled in to the object:
lib/auto/Foo/Bar/Bar.so
lib/auto/Foo/Bar/Bar.inl
(The .inl component contains dependency information to make
sure the source code is in sync with the executable)
If you don't use "name",
Inline will pick a name for you based on your program name or package
name. In this case, Inline will also enable the
"autoname" option which mangles in a
small piece of the MD5 fingerprint into your object name, to make it
unique.
- "autoname"
- This option is enabled whenever the
"name" parameter is not specified. To
disable it say:
use Inline C => 'DATA',
disable => 'autoname';
"autoname" mangles in enough
of the MD5 fingerprint to make your module name unique. Objects created
with "autoname" will never get
replaced. That also means they will never get cleaned up
automatically.
"autoname" is very useful
for small throw away scripts. For more serious things, always use the
"name" option.
- "version"
- Specifies the version number of the Inline extension object. It is used
only for modules, and it must match the global variable
$VERSION. Additionally, this option should used if
(and only if) a module is being set up to be installed permanently into
the Perl sitelib tree using Inline::MakeMaker (NOT used by
Inline::Module). Inline will croak if you use it otherwise.
The presence of the
"version" parameter is the official
way to let Inline know that your code is an installable/installed
module. Inline will never generate an object in the temporary cache
("_Inline/" directory) if
"version" is set. It will also never
try to recompile a module that was installed into someone's Perl site
tree.
So the basic rule is develop without
"version", and deliver with
"version".
- "with"
- "with" can also be used as a
configuration option instead of using the special 'with' syntax. Do this
if you want to use different sections of Inline code with different
modules. (Probably a very rare usage)
use Event;
use Inline C => DATA => with => 'Event';
Modules specified using the config form of
"with" will not be
automatically required. You must "use"
them yourself.
- "using"
- You can override modules that get used by ILSMs with the
"using" option. This is typically used
to override the default parser for Inline::C, but might be used by any
ILSM for any purpose.
use Inline config => using => '::Parser::RecDescent';
use Inline C => '...';
This would tell Inline::C to use
Inline::C::Parser::RecDescent.
- "global_load"
- This option is for compiled languages only. It tells Inline to tell
DynaLoader to load an object file in such a way that its symbols can be
dynamically resolved by other object files. May not work on all platforms.
See the "global" shortcut below.
- "untaint"
- You can use this option whenever you use Perl's
"-T" switch, for taint checking. This
option tells Inline to blindly untaint all tainted variables. (This is
generally considered to be an appallingly insecure thing to do, and not to
be recommended - but the option is there for you to use if you want.
Please consider using something other than Inline for scripts that need
taint checking.) It also turns on
"safemode" by default. See the
"untaint" shortcut below. You will see
warnings about blindly untainting fields in both
%ENV and Inline objects. If you want to silence
these warnings, set the Config option
"no_untaint_warn" => 1. There can be
some problems untainting Inline scripts where older versions of Cwd, such
as those that shipped with early versions of perl-5.8 (and earlier), are
installed. Updating Cwd will probably solve these problems.
- safemode
- Perform extra safety checking, in an attempt to thwart malicious code.
This option cannot guarantee security, but it does turn on all the
currently implemented checks. (Currently, the only "currently
implemented check" is to ensure that the
"directory" option has also been used.)
There is a slight startup penalty by using
"safemode". Also, using
"untaint" automatically turns this
option on. If you need your code to start faster under
"-T" (taint) checking, you'll need to
turn this option off manually. Only do this if you are not worried about
security risks. See the "unsafe"
shortcut below.
- "force_build"
- Makes Inline build (compile) the source code every time the program is
run. The default is 0. See the "force"
shortcut below.
- "build_noisy"
- Tells ILSMs that they should dump build messages to the terminal rather
than be silent about all the build details.
- "build_timers"
- Tells ILSMs to print timing information about how long each build phase
took. Usually requires
"Time::HiRes".
- "clean_after_build"
- Tells Inline to clean up the current build area if the build was
successful. Sometimes you want to
"disable" this for debugging. Default is
1. See the "noclean" shortcut
below.
- "clean_build_area"
- Tells Inline to clean up the old build areas within the entire Inline
"directory". Default is 0. See the
"clean" shortcut below.
- "print_info"
- Tells Inline to print various information about the source code. Default
is 0. See the "info" shortcut
below.
- "print_version"
- Tells Inline to print version info about itself. Default is 0. See the
"version" shortcut below.
- "reportbug"
- Puts Inline into 'reportbug' mode, which is what you want if you desire to
report a bug.
- "rewrite_config_file"
- Default is 0, but setting "rewrite_config_file =>
1" will mean that the existing configuration file in the
Inline "directory" will be overwritten.
(This is useful if the existing config file is not up to date as regards
supported languages.)
- "warnings"
- This option tells Inline whether to print certain warnings. Default is
1.
This is a list of all the shortcut configuration options currently available for
Inline. Specify them from the command line when running Inline scripts.
perl -MInline=noclean inline_script.pl
or
perl -MInline=info,force,noclean inline_script.pl
You can specify multiple shortcuts separated by commas. They are
not case sensitive. You can also specify shortcuts inside the Inline program
like this:
use Inline 'info', 'force', 'noclean';
NOTE: If a 'use Inline' statement is used
to set shortcuts, it can not be
used for additional purposes.
- "clean"
- Tells Inline to remove any build directories that may be lying around in
your build area. Normally these directories get removed immediately after
a successful build. Exceptions are when the build fails, or when you use
the "noclean" or
"reportbug" options.
- "force"
- Forces the code to be recompiled, even if everything is up to date.
- "global"
- Turns on the "global_load" option.
- "info"
- This is a very useful option when you want to know what's going on under
the hood. It tells Inline to print helpful information to
"STDERR". Among the things that get
printed is a list of which Inline functions were successfully bound to
Perl.
- "noclean"
- Tells Inline to leave the build files after compiling.
- "noisy"
- Use the "build_noisy" option to print
messages during a build.
- "reportbug"
- Puts Inline into "reportbug" mode, which
does special processing when you want to report a bug.
"reportbug" also automatically forces a
build, and doesn't clean up afterwards. This is so that you can tar and
mail the build directory to me.
"reportbug" will print exact
instructions on what to do. Please read and follow them carefully.
NOTE: "reportbug" informs
you to use the tar command. If your system does not
have tar, please use the equivalent
"zip" command.
- "safe"
- Turns "safemode" on.
"untaint" will turn this on
automatically. While this mode performs extra security checking, it does
not guarantee safety.
- "site_install"
- This parameter used to be used for creating installable Inline modules. It
has been removed from Inline altogether and replaced with a much simpler
and more powerful mechanism,
"Inline::MakeMaker". See the section
below on how to create modules with Inline.
- "_testing"
- Used internally by Ct09parser.t and Ct10callback.t(in the
Inline::C test suite). Setting this option with Inline::C will mean that
files named "parser_id" and
"void_test" are created in the
"./Inline_test" directory, creating that
directory if it doesn't already exist. The files (but not the
"./Inline_test directory") are cleaned
up by calling
"Inline::C::_testing_cleanup()". Also
used by "t/06rewrite_config.t" to
trigger a warning.
- "timers"
- Turn on "build_timers" to get extra
diagnostic info about builds.
- "unsafe"
- Turns "safemode" off. Use this in
combination with "untaint" for slightly
faster startup time under "-T". Only use
this if you are sure the environment is safe.
- "untaint"
- Turn the "untaint" option on. Used with
"-T" switch. In terms of secure
practices, this is definitely not a recommended way of dealing with
taint checking, but it's the only option currently available with
Inline. Use it at your own risk.
- "version"
- Tells Inline to report its release version.
The current preferred way to author CPAN modules with Inline is to use
Inline::Module (distributed separately). Inline ships with Inline::MakeMaker,
which helps you set up a Makefile.PL that invokes Inline at install time to
compile all the code before it gets installed, but the resulting module still
depends on Inline and the language support module like Inline::C. In order to
avoid this dependency, what you really want to do is convert your distribution
to plain XS before uploading it to CPAN. Inline::Module fills that role, and
also integrates well with more modern authoring tools.
See Inline::Module for details on that approach, or continue
reading below for the older Inline::MakeMaker technique.
Let's say that you wanted to write a module called
"Math::Simple". Start by using the
following command:
h2xs -PAXn Math::Simple
This will generate a bunch of files that form a skeleton of what
you need for a distributable module. (Read the h2xs manpage to find out what
the options do) Next, modify the
"Simple.pm" file to look like this:
package Math::Simple;
$VERSION = '1.23';
use base 'Exporter';
@EXPORT_OK = qw(add subtract);
use strict;
use Inline C => 'DATA',
version => '1.23',
name => 'Math::Simple';
# The following Inline->init() call is optional - see below for more info.
#Inline->init();
1;
__DATA__
=pod
=cut
__C__
int add(int x, int y) {
return x + y;
}
int subtract(int x, int y) {
return x - y;
}
The important things to note here are that you must specify
a "name" and
"version" parameter. The
"name" must match your module's package
name. The "version" parameter must match
your module's $VERSION variable and they must be
considered valid by "version::parse".
NOTE: These are Inline's sanity checks to make sure you know what
you're doing
before uploading your code to CPAN. They insure that once the module has
been installed on someone's system, the module would not get
automatically recompiled for any reason. This makes Inline based modules
work in exactly the same manner as XS based ones.
Finally, you need to modify the Makefile.PL. Simply change:
use ExtUtils::MakeMaker;
to
use Inline::MakeMaker;
And, in order that the module build work correctly in the cpan
shell, add the following directive to the Makefile.PL's
WriteMakefile():
CONFIGURE_REQUIRES => {
'Inline::MakeMaker' => 0.45,
'ExtUtils::MakeMaker' => 6.52,
},
This "CONFIGURE_REQUIRES"
directive ensures that the cpan shell will install Inline on the user's
machine (if it's not already present) before building your Inline-based
module. Specifying of "ExtUtils::MakeMaker => 6.52," is
optional, and can be omitted if you like. It ensures only that some harmless
warnings relating to the
"CONFIGURE_REQUIRES" directive won't be
emitted during the building of the module. It also means, of course, that
ExtUtils::Makemaker will first be updated on the user's machine unless the
user already has version 6.52 or later.
If the "Inline->init();" is not done then,
having installed Math::Simple, a warning that "One or more DATA
sections were not processed by Inline" will appear when (and only when)
Math::Simple is loaded by a "require call. It's a harmless warning -
and if you're prepared to live with it, then there's no need to make the
"Inline->init();" call.
When the person installing
"Math::Simple" does a
""make"", the generated Makefile
will invoke Inline in such a way that the C code will be compiled and the
executable code will be placed into the
"./blib" directory. Then when a
""make install"" is done, the
module will be copied into the appropriate Perl sitelib directory (which is
where an installed module should go).
Now all you need to do is:
perl Makefile.PL
make dist
That will generate the file
"Math-Simple-0.20.tar.gz" which is a
distributable package. (It will also generate some harmless warnings in
relation to "CONFIGURE_REQUIRES" unless
the version of your ExtUtils::MakeMaker is 6.52 or later.) That's all there
is to it.
IMPORTANT NOTE: Although the above steps will produce a
workable module, you still have a few more responsibilities as a budding new
CPAN author. You need to write lots of documentation and write lots of
tests. Take a look at some of the better CPAN modules for ideas on creating
a killer test harness. Actually, don't listen to me, go read these:
- perldoc perlnewmod
- <http://www.cpan.org/modules/04pause.html>
- <http://www.cpan.org/modules/00modlist.long.html>
In reality, Inline just automates everything you would need to do if you were
going to do it by hand (using XS, etc).
Inline performs the following steps:
- Receive the Source Code
Inline gets the source code from your script or module with a
statements like the following:
use Inline C => "Source-Code";
or
use Inline;
bind Inline C => "Source-Code";
where "C" is the programming
language of the source code, and "Source-
Code" is a string, a file name, an array
reference, or the special 'DATA' keyword.
Since Inline is coded in a
""use"" statement,
everything is done during Perl's compile time. If anything needs to be
done that will affect the "Source-
Code", it needs to be done in a
"BEGIN" block that is before
the ""use Inline
..."" statement. If you really need to specify code to
Inline at runtime, you can use the
"bind()" method.
Source code that is stowed in the
'DATA' section of your code, is read in by an
"INIT" subroutine in Inline. That's
because the "DATA" filehandle is not
available at compile time.
- Check if the Source Code has been Built
Inline only needs to build the source code if it has not yet
been built. It accomplishes this seemingly magical task in an extremely
simple and straightforward manner. It runs the source text through the
"Digest::MD5" module to produce a
128-bit "fingerprint" which is virtually unique. The
fingerprint along with a bunch of other contingency information is
stored in a ".inl" file that sits next
to your executable object. For instance, the
"C" code from a script called
"example.pl" might create these
files:
example_pl_3a9a.so
example_pl_3a9a.inl
If all the contingency information matches the values stored
in the ".inl" file, then proceed to
step 8. (No compilation is necessary)
- Find a Place to Build and Install
At this point Inline knows it needs to build the source code.
The first thing to figure out is where to create the great big mess
associated with compilation, and where to put the object when it's
done.
By default Inline will try to build and install under the
first place that meets one of the following conditions:
- 1.
- The DIRECTORY= config option; if specified
- 2.
- The "PERL_INLINE_DIRECTORY" environment
variable; if set
- 3.
- ".Inline/" (in current directory); if
exists and "$PWD != $HOME"
- 4.
- bin.Inline (in directory of your script); if exists
- 5.
- "~/.Inline/" - if exists
- 6.
- "./_Inline/" - if exists
- 7.
- "bin/_Inline" - if exists
- 8.
- Create "./_Inline/" - if possible
- 9.
- Create "bin/_Inline/" - if possible
Failing that, Inline will croak. This is rare and easily remedied
by just making a directory that Inline will use.
If the "PERL_INSTALL_ROOT"
Environment Variable has been set, you will need to make special provision
for that if the 'make install' phase of your Inline scripts are to
succeed.
If the module option is being compiled for permanent installation,
then Inline will only use "./_Inline/" to
build in, and the $Config{installsitearch} directory
to install the executable in. This action is caused by Inline::MakeMaker,
and is intended to be used in modules that are to be distributed on the
CPAN, so that they get installed in the proper place.
- Parse the Source for Semantic Cues
Inline::C uses the module
"Parse::RecDescent" to parse through
your chunks of C source code and look for things that it can create
run-time bindings to. In "C" it looks
for all of the function definitions and breaks them down into names and
data types. These elements are used to correctly bind the
"C" function to a
"Perl" subroutine. Other Inline
languages like Python and Java actually use the
"python" and
"javac" modules to parse the Inline
code.
- Create the Build Environment
Now Inline can take all of the gathered information and create
an environment to build your source code into an executable. Without
going into all the details, it just creates the appropriate directories,
creates the appropriate source files including an XS file (for C) and a
"Makefile.PL".
- Build the Code and Install the Executable
The planets are in alignment. Now for the easy part. Inline
just does what you would do to install a module. "`perl Makefile.PL
&& make && make test && make install>".
If something goes awry, Inline will croak with a message indicating
where to look for more info.
- Tidy Up
By default, Inline will remove all of the mess created by the
build process, assuming that everything worked. If the build fails,
Inline will leave everything intact, so that you can debug your errors.
Setting the "noclean" shortcut option
will also stop Inline from cleaning up.
- DynaLoad the Executable
For C (and C++), Inline uses the
"DynaLoader::bootstrap" method to pull
your external module into "Perl"
space. Now you can call all of your external functions like Perl
subroutines.
Other languages like Python and Java, provide their own
loaders.
For information about using Inline with C see Inline::C.
For sample programs using Inline with C see
Inline::C-Cookbook.
For "Formerly Answered Questions" about Inline, see
Inline-FAQ.
For information on supported languages and platforms see
Inline-Support.
For information on writing your own Inline Language Support
Module, see Inline-API.
Inline's mailing list is inline@perl.org
To subscribe, send email to inline-subscribe@perl.org
When reporting a bug, please do the following:
- Put "use Inline 'reportbug';" at the top of your code, or use
the command line option "perl -MInline=reportbug ...".
- Run your code.
- Follow the printed directions.
Ingy döt Net <ingy@cpan.org>
Sisyphus <sisyphus@cpan.org> fixed some bugs and is current
co-maintainer.
- Copyright 2000-2019. Ingy döt Net.
- Copyright 2008, 2010-2014. Sisyphus.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
See <http://www.perl.com/perl/misc/Artistic.html>
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